Suggestion: Improving post findability

I was reading a discussion about this on here earlier today, and I've already lost it! 😬 Sorry if this is just creating more noise, but we clearly need better ways to find content. The search feature will go a long way, but here are some other ideas:

Tag search. On any topic with tags, the tags should be clickable links to URLs like https://tildes.net/tag/elder+scrolls. This page would show all topics that use that tag, with sort and filter options. There should be a way (maybe built into the search form) to type any tag and jump straight to this page.

Recently viewed topics list. Reddit shows a sidebar listing the last n posts you viewed. It's admittedly a little creepy seeing your history displayed like that, but it's a useful way to jump back into conversations for follow-up later. The old Reddit design had a "clear" button to delete the history, but curiously that is no longer present in the redesign. (Privacy features like that should not be overlooked here.)

Saved topics. Another feature from Reddit. Every post has a "Save" link below it, that adds the post to your personal saved posts list, which can reached from your profile. Saved post lists are only visible to the users that own them.

Repost detection. I really like how Ask MetaFilter helps posters make sure their content is fresh before they publish it. The submit button under the new post form is labeled "Preview" and clicking it shows what the post will look like before publishing it. This gives posters the opportunity to proofread and ensure their text formatting is correct. More importantly, the site scans the content of the post and displays a list of five possible existing posts that match it:

The following previously-posted questions might be related to the question you're asking. Please take a look before posting to see if any of these answer your question.

This flow adds an additional click before you can actually post, but I think it's for the best. The slowdown politely nudges you toward considering the quality and originality of what you're about to say, without being overbearing. The main MetaFilter site also checks all URLs you enter to see if anyone has posted them before. Note that these tools don't prevent anyone from posting, they just empower users to avoid reposting and reinforce good posting behaviors.

Repost flagging. I have a half-baked idea about allowing users to flag topics as reposts, but I haven't seen this implemented before. This would be separate from voting. A user wishing to flag a topic would be asked to provide the URL of an existing topic it duplicates. This wouldn't affect the topic itself, other than to add a small banner to the top of the page: "n users flagged this as a repost of the following topics: [list of links]". Then anyone would have the ability to [agree], [disagree], or append a link to the list. Public consensus would affect the future of the topic... if enough others agree the topic is redundant, it could be auto-deleted or just algorithmically prioritized lower than non-reposts. If enough disagree, the flag could be auto-removed from the topic. The usernames of the flaggers should be public, and there should be a way to view both a user's frequency of flagging and whether consensus agreed with those flags. Accountability would be important for this sort of system.

Ability to subscribe to users. I saw the other feature request for a "friend" mechanic. I agree with the commenters who said it would be too much like a social network. However, I could see a use case for a "Subscribe" button on a user's profile page, just like the ones on group pages. This would cause all topics posted by that user to be included in your main page, even if they are in groups you aren't subscribed to.

I'd be interested to hear your feedback on these suggestions, as well as other ideas specific to increasing content visibility.